Manufacture of incandescent gas mantles



Patented Get. 5, 1926.

ret na earsu'r (JFZTEQE;

THOMAS TERRELL, OF TEMPLE, LONDON, ENGLAND. i

"HEANUFACTURE G EIICANDESCENT GAS IIIANTLES.

No Drawing. Application filed. November 7, 1925 Serial No. 67,698, and 1924. i

V/hen gas mantles were first manufactured they were produced as follows :A natural cotton knitted fabric was dipped in-a solution of salts (nitrate of thorium with about 1 per cent nitrate of cerium)- and dried. the fabric was then burned out with a Bunsen ,Q'as flame and left, as a simulacrum of the fabric, a residue of the oxides of the rare earths used. The elementary fibres of the cotton thread being more or less tubular and twisted the oXide res dues had a similar form. they were very brittle and being the result of the a destructive burning of the nitrates had a moreor less volcanic annean ance under the microscope. It was subsequently discovered that a ramie fibre had great advantage over cotton in that being more solid and not twisted it nroduced a better ash and consequently ramie was very generally substituted for cotton but there was this disadvantage that the ramie thread was much coarser than the cotton thread and consequently in the unburned mantle the percentage of organic to inorganic material was much higher: this resulted in the finished mantle being much more porous and coarse in proportion to its actual weight. It h ad been thought that artificial silk would produce a better mantle than either ramie or cotton but all attempts to use it failed until Plaiscetty conceived the idea of denitratthe salts before incineration. This he did by dinning; the knitted fabric in 'the'sa'lt solution, drying it, and then dinning it in a solution of ammonia gas, washing out the the nitrate of ammonia and again and the result was a mantle composed of cellulose and oxides of the rare earths in solid solution. It was afterwards discovered that cotton could be successfully used in the same way but the defects of the cotton mantle-to very large extent remained. It was generally considered that a mantle say of the size known in the British trade as a universal inverted. mantle should when finished contain .5 grams of oxides and that its durability and strength depended upon this weight being annroximated.

The elementary fibres of the artificial silk heretofore used in the manufacture of mantles were of a thickness equivalent to from 5 to 7 deniers Italian London silk conditioning house measurement hereinafter referred to as Italian silk measurement) and the thread used to knit the fabric for the manin Great Britain Jll'ovember 21,

tles was from 1&0 to 200 deniers. This was considered necessary to produce the weight mentioned above of .5 grams per mantle.

I have ascertained that the strength and durability of a mantle does not depend upon hea-vv wei aht of oxides but unon the fineness of the elementary fibres of which it is composed and further that when a very fine fibre is used say of to 3 de niers in thickness they may be spun or thrown to produce very fine yarn of say 1/100 to 1/80 metric measurement or even less and that when this yarn is knitted and dinned a mantle can be made of the size mentioned containing only .2 to .25 grams weight of oxides ancthatthis mantle is very superior in strength; durability and in light emission to any mantle hitherto manufactured. By" metric measurement is meant'nroportion of length to weight. The experiments which I have conducted lead me to the conclusion that if it were possible to knit and form a mantle out of a single strand of cellulose line as the fibre of a sniders web and din and burn it. there would be produced the strongest and most durable mantle possible in actual use and its light emission would vbeof the best.

My invention consists in using; aflustra cellulose fibre which is made as fine'asjpos sible say from .5 to 3 deniers Italian silk measurement in thickness. In practising the invention I nrefer to use fibre of l-denier in thickness and to throw or sninthis fibre into yarn of 1/100'to 1/40 metric measurement approximately (preferably 1/80) and to use such yarn in the manufacture of the mantles. If I am making the universal mantles I have already referred to I prefer to knit this yarn on a 160 needle machine having; a cylinder 9 centimetres in diameter and I knit with 5 rows of stitches to each centimetre. I clip this material conveniently in a ner cent solution of the salts and throw out the solution therefrom so that 100 grams dry shall weigh 200-800 grams when impregnated and wet. I dry, denitrate, and dry again. The result will be approximately that 100 grams of the original fabric will give 12F-150 grams of impregnated material-calculated chemically dry. A universal mantle of this manufacture in which yarn of 1/80 metric measurement has been used as aforesaid may be made to contain as low .mantles'made from it.need not .beburned as .25 grams of oxide. A mantle made of this material and in this manner will Weigh in both lustra cellulose and thorium oxide just about half that of a mantle made by any process hitherto in vogue and yet will be considerably stronger and more durable and more light emitting.

Another great advantage of the present invention arising from the fact that the elementary fibre of the lustra cellulose is ex tremely fine is thatthe fibre being so fineit is very soft and its teXturehas thefeeling of fine-wool in theplace'of the harslrtexture of ordinary artificial silk or of-ramieor even of natural-cotton. Thesubstanee when im- .pregnated preserves tthis softness and the off in the-factory to get th eir.proper sh ape they may beput onirings andsolt. in that con.di

.tion. The buyer can place a mantle on his ordinary .burnerand light it sons .to burn .out the organic matter. and he canthen turn on the gasandzevennt a pressure of 5 cm. of water .or less the .gas wilhacting on thi verysoft material, blow .it out to its proper shape-so that it b comes nndistinguishable from a mantle burned oifat the factory and sold, as it is technically termed, hard? llo soft mantles although many have been sold in that condition have ever beforepresented this advantage and there is this further advantagethat soft mantles made according to the present invention have a fully efficient life of over 2000 ho rs continuous burning Whichhitherto no mantle however made has approached. The shrinkage on continuous burning is;practically nil and the fibres being so very fine they attain the highest temperature the flame will give and the light emitted is consequently very white. 7

A soft'mantle made according to the-in- ,vention of the size of a universal inverted ,.m-antle as aforesaid would contain aboutb gramsof lust-ra cellulose and .25 to .80 grams of oxide. a In construingthis specification 1/40 metric measurement means 40,629 metres per kilogram .and '1/100-means 101,573 metres per kilogramand other counts in proportion 1,co1,74.e

there has been used lustra cellulose thethickness of tie elementary fibre ofwhichis withinth'e range of .5 to 3 deniers vItalian silk measurement.

2. An incandescent mantle in the marketablesoft conditionhavinga fabric of lustraccllulose the elementary fibre of which has a thickness withinthe range of..5 vto 3 deniers Italian silk measurement.

An incandescent gas -mantle in which there has been used yarn of aweightnottezz- .ceeding 1/40 metric measurement and such yarn beingcomposed of lustra cellulose the thickness of the elementary fibre of which is withinthe range of .5 to 3 deniers rtalian. silk measurement.

4. An incandescent gas .mantle in the marketable soft condition having fabric of yarn not exceeding 1/40 metric measurement, such yarn being composed of lustra cellulose the elementary fibre of which has a thickness Within the -.ra-nge of .5 to 3 deniers Italian silk measurement.

5. An inverted incandescentgas mantle of the size known in the British trade as a universal inverted mantle containingfrom .25 gramslto .30 gramsof oxide.

.6. An inverted incandescent gasmantle-in the marketable soft condition and of the siZeknown-in the British trade as a univen sal inverted mantle having a fabric of .lustra celluloseof about .5 grams in weight of .lustra cellulose and containing from to .30 gramsof oxide.

THOMAS rnnmam... 

